Hydroxyalkylamines



Jan. 15, 1935.

No/ of lsopmpanolamlhe in React/0n Produc J. N. WICKERTHYDROXYALKYLAMINES Filed Jan. 16, 1952 2 Sheets-Sheet 1' 1/ 7/775opropano/om/ne 0171s opropano/am/ne Ma/m/Isaprapa/m/am/he Mo/s 0fPropy/ene OX/de Added /0 /00 /70/5 0/ Ammo/77a INVENTQR'. fzdzmt,

BY I ATTORNEYS Jan. 15, 1935. J. N. WICKERT 1,988,225

HYDROXVALKYLAMINES Filed Jan. 16, 1932 2 Sheets-Shee t 2 u l'- FATTORNEYS arched it I I I v I 1,988,223

UNITED STATES PATENT OFFICE 1,988,225 HYDROXYALKYLAMINES Jacob N.Wiekert, South Charleston, W. Va., assignor to Carbide and CarbonChemicals Corporation, a corporation of New York Application January16,1932, sci-in No. 531,040 comma. (Cl. 260-127) Numerous investigatorshave disclosed experi- Table 4 mental data on the condensation ofethylene oxide with ammonia to form a mixture of the MoLpu'centoialninein ethanolamines, but the prior art discloses little p 6information concerning the behavior of the high- 100 me er alkyleneoxides with ammonia. The present Mono- Div Triinvention has as its chiefobject the disclosure of I the heretofore undescribed isopropanolamines300 o o 100 and the conditions under which they are prefg g I 10 erablyto be formed from propylene oxide and 100 17 44 so l0 ammonia. 23

A detailed experimental investigation has led to the discovery oiheretofore unknown facts con- From h curves shown in Figure 1 e thecerning the preparation and properties of the isocompanymg drawings asomewhat clearer underpropanolamines of the formula (C3H'IO)nNHx,Standing may be obtained of these e ti n p 13 where n equals 1, 2 or 3,and a: equals 3 minus of the reactants and the three products. The One,two or three molecules of propylene oxcurves of w eonstllleted y d aw gide may react with one molecule of ammonia, as smooth curves through hep mt Obtained by follows: plotting the values given in Table A onsuitable C3HsO+NH3=C3H1ONH2 (monoisopropanol- From these it is Seen thatit is 1 20 amine sible to secure a product comprising substan-2C3H6O+NH3= (canqohNn (diisopmpanob tially all monoisopropanolamine orsubstantially amine all triisopropanolamine, or equal proportions of3C3H0C+NH3= (Cal-T10) 3N (triisopropanolamine) any two of the mines, y001115101 01 the relative 25 The hydroxyl groups of thelsopropanolamjnes concentrations of the reactants. For example, g

so formed tend to react to form heavier and a Product containing thanabout 01 more complex compounds. I have found that tllisopl'opanolamme 1be made}! the total this tendency is greater at higher temperatures,quantityot Propylene oxlde added 15 more then so it is desirable to keepthe reacting mixture about 80% of the amount required by he aqua at orbelowabout 55 C. Furthermore, since tion 3C3H60+NI8-(C3H10)3N- so thereactions between ammonia and propylene have determmed some of the 1 1 8819101 oxide are exothermic, it is necessary to cool the erhee of thethree pu i p o a olamines. and reacting mixture in order to prevent anundesirin Taple B they a1e mmpal'ed with t correable rise in temperatureof the reaction mixture. spondmg Pmpertles of the ethanolemines- I havefurther found that it is desirable to Table 3 8i avoid an excess ofunreacted propylene oxide in the mixture, for if an excess of unreactedoxide is Specific Boning present, the reaction will proceed withdangerous gravi y p int at violence. A suitable method of preventing theWW accumulation of such an excess is to distribute 40 the oxide gas asvery fine bubbles in the ammoms Ii uid. as by diffusing the gas thro$$3i3%%%i$tfi::: 9:33; iii '33 iii a porous ceramic article which isimmersed in fi g gl i-gig {g 5 3-? the liquid. The rate of diffusion ofthe gas gigg igi fif 156 1 11:75

through the. porous article may easily be con- Triethenolemlne-n 11-3046 trolled by regulating the gas pressure.

My experiments have led to the discovery of y experimental method isindicated y the the relative proportions of the threeisophopanolfollowing p wherein Specific reference i amines which areobtained in the product when made to the appa Shown diagrammatically 50various amounts of propylene oxide are added in Figure 2 0 the accmpanying drawings. A 50 to a certain amount of ammonia. The mol perflask10 was equip with a mechanical ti er cent of each of the amines obtainedin the reac- 11 and mounted in a. water bath 12 having cold tion mixtureby adding various amounts of propywater circulation means. Into a sideneck of lene oxide to one hundred mols of ammonia is the flask 10 wasmounted a thermometer 13, and

shown in Table A. into another side neck were fitted an inlet tube 55 14reaching to the bottom of the flask 10 and an outlet tube 15. which wasconnected to a manometer 16. On the bottom of the inlet tube 14 was aporous diffuser 17 consisting of a closed-end porous ceramic cylinder.Another flask 20 served as, a propylene oxide vaporizer, and wasconnected through a tube 18 to the inlet tube 14 of the reaction flask.The vaporizer flask was heated by a water bath 21 and its temperature soregulated that the propylene oxide vapors would be diffused into theammonia about as fast as they were used up in the reaction.

Concentrated aqua ammonia (28% NH3) was placed in the reaction flask 10and the stirrer 11 was started. The propylene oxide was bubbled as avapor into this solution. When the heatof the reaction had raised thetemperature to 45 0., the cooling water was started circulating throughthe bath 12 slowly and the temperature of the reacting liquid was heldbetween 45 C. and C. for the rest of the experiment. The rate ofaddition of propylene oxide vapor was regulated by the pressure on thesystem as registered on the manometer 16. The pressure was kept atamospheric until the reaction was well started and later was keptslightly less than atmospheric by the absorption of propylene oxide fromthe vapors in the flask 10. After all the propylene oxide had beenadded, the system was allowed to stand with the stirrer 11 running forabout a half hour, during which time the temperature in flask 10 slowlydropped to that of the room. The product was then stored in a stopperedflask until it could be distilled.

The distillation of the product was carried out in two steps. The waterand unreacted material were distilled off under about 20 inches vacuumand at -70 C. This distillate was analyzed for organic amines and in nocase showed more than a trace. The residue was then distilled at 5 mm.according to common procedure, using oil heating. The-lowest-boilingfraction started distilling at 65 C. but the temperature soon settled to45 C. as the monoisopropanolamine was distilled out. The next fractiondistilled at 116 C. to give a clear waterwhite liquid of rather highviscosity that soon solidified to a colorless crystalline mass. This wasthe diamine. The triisopropanolamine distilled slowly at 145 C. and gavea heavy, slightly yellow oil that soon solidified to colorless crystals.Each fraction distilled over at a very sharply deflned temperature, andpractically no material distilled at temperatures between those givenabove. The residue after removal of the triisopropanolamine was verysmall, and had about the same equivalent weight as the triamine. Eachfraction was examined for specific gravity, equivalent weight, freezingpoint, and alkalinity by standard methods. Y

I claim:

1. The method of producing a mixture of isopropanolamines containingmore than about 90% of triisopropanolamine which comprises addingpropylene oxide to an aqueous solution of ammonia in such amount thatthe propylene oxide so added is more than about of the amount requiredby the equation 2. The method as claimed in claim 1 in which thetemperature is maintained below about 55 C.

3. The method of producing isopropanolamines which comprises graduallydiffusing propylene oxide into an aqueous solution of ammonimthe totalquantity of propylene oxide added being not greater than the amountrequired by the equation 3C3HsO+NH3- (CaH'zO) 3N, while maintaining thetemperature of said solution below about 55 C.

4. As a chemical compound, a polyisopropanoh JACOB N. WICKERT.

